1. Field
The present specification relates to a light-emitting element and a method for manufacturing the light-emitting element, and particularly to a light-emitting element using quantum dots and a method for manufacturing the light-emitting element.
2. Description of the Related Art
A semiconductor light-emitting element using a semiconductor island structure (quantum dot) has been known (Japanese Unexamined Patent Application Publication No. 2003-332695). Such the semiconductor light-emitting element has a structure of n-type AlGaAs/n-type GaAs/InGaAs island structure/nitrogen-containing compound semiconductor/p-type GaAs/p-type AlGaAs.
The InGaAs island structure has internal stress that comes from compressive stress whereas the nitrogen-containing compound semiconductor has tensile stress. Thus, the internal stress of the InGaAs island structure is reduced by disposing the nitrogen-containing compound semiconductor so as to be in contact with the InGaAs island structure.
As a result, the internal stress of the InGaAs island structure, which is a light-emitting layer, is reduced and an emission spectrum of 1.55 μm is achieved at room temperature.
However, since a quantum dot itself, which is a light-emitting layer, is not controlled to be p-type or n-type in known semiconductor light-emitting elements, the amount of carriers (electrons and holes) injected into the light-emitting layer is small, which causes a problem in that light-emitting efficiency is low.